The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, the approaches described in this section may not be prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Some printing devices are configured with a feature known as “locked printing” to provide control over the printing of electronic documents. When the locked printing feature is enabled and print data is sent to the printing device, processing of the print data is deferred until a user enters authentication data at the printing device and the authentication data is verified. The authentication data typically includes a user ID and/or password, although many different types of authentication data may be used. A user enters the authentication data through an operation panel on the printing device and the printing device verifies the authentication data. Once the authentication data is successfully verified, the printing device allows the print data to be processed, i.e., allows a printed version of the electronic document reflected in the print data to be generated.
One of the problems with conventional locked printing approaches is that a user must enter the authentication data using the user interface provided on the printing device. User interfaces on printing devices often consist of a simple operation panel with a limited number of status indicators and function buttons. For example, a typical operation panel may include status lights that indicate whether a printing device is in a “ready” state, requires attention or is in an error state. The typical operation panel may also include buttons for resetting a print job, canceling a print job, turning the printing device online or offline and a “go” button for overriding a warning or error condition. An operation panel may also include a menu button and one or more “select” buttons that allow a user to view and navigate through a series of menu options. For example, the select buttons may include “+” and “−” or “<” and “>” buttons for menu navigation. Printing devices conventionally do not include full or even partial keyboards for entering characters and numbers, which makes entering authentication data in the form of an alphanumeric string tedious and time consuming. Some printing devices include a numeric keypad for entering a number of copies. Entering characters is tedious using a keypad because each number key must be associated with multiple characters and therefore entering a character string using a numeric keypad can require a large number of button presses. This process is further complicated in situations where the authentication data is in the form of case sensitive alphanumeric strings. Thus, entering authentication data, such as a user ID and password, using the user interface conventionally available on printing devices is tedious and not user friendly. Based on the foregoing, there is a need for an approach for implementing locked printing on printing devices that does not suffer from limitations of prior approaches.